1. Field of the Invention
This invention relates to an improved control device of the differential pressure type and to a method of making the same.
2. Prior Art Statement
It is known to provide a control device having a housing means provided with an actuator chamber separated from a pressure differential chamber by wall means having opening means therethrough receiving an axially movable actuator pin that transmits axial movement of a movable part in the pressure differential chamber, the actuator pin being separate from and engageable with the movable part to the actuator chamber.
For example, see the following U.S. Patent:
(1) U.S. Pat. No. 3,989,910--Russell et al.
It appears that the pressure differential control device of item (1) above has the actuator pin thereof operate a lever system for controlling an electrical switch, the range spring that is operatively interconnected to the actuator pin having one end thereof adjustably carried by the cover of the housing means.
It is also known to have an optical switch means interrupter carried by a diaphragm assembly which will move the interrupter relative to the optical switch unit in relation to the position of the diaphragm assembly in the housing means carrying the same.
For example, see the following U.S. Patent:
(2) U.S. Pat. No. 4,122,337--Okuda et al
It appears that in every embodiment of the pressure electrical signal conversion means of item (2) above, the light interrupter plate is fastened to its movable diaphragm assembly so as to move in unison therewith, the interrupter plate being disposed intermediate a photosensitive cell means and a light soure means.